Hopefully I can get more answers here than in the Electronics forum... I have finally found a common link to ALL of my problems--heat. The hotter the engine gets, the worse the problems get. When the engine coolant temp is <100* F, the engine will NOT idle, but the torque convertor will lock if I am going that fast. As the temp rises, so does the idle speed, so much so that at operating temperatures, the engine, no-load, no-brakes, idles at 1500 RPM . However, at operating temp, the torque convertor will NOT lock at 60 MPH, which is where I try to keep it around here, since the limit is 55 and my insurance is high enough as it is .

I'm thinking that either the CTS, IAT, or TPS has something to do with this since they are the only common links I have here. Also, I don't seem to enter closed loop for some reason, and the coolant fan comes on around 195* F (yes, I did measure that with a thermometer). Gas prices here are ridiculous, not to say they aren't anywhere else, but I'm burning WAAY too much gas.

 

All electronic parts hate heat, as they get older, they are more likely to fail under the stress. If the TPS heats up and the ground ends up getting a higher resistance because of the heat, than more voltage will default through the signal wire and the ECM will think that you have your foot into it more. That'll cause enrichment and high idle, and if it's bad enough, will prevent the TC from locking.

Here's how you can check it. Backprobe the connections for the CTS (coolant temp) and see if the decreases with engine temp. if it does, and doesn't spike upward, it's okay.

Do the same with the TPS Signal and make sure that it doesn't have any upward spikes after it's heated up.

Those are your 2 most likely culprits.

Good Luck,
Jeff

 

Okay. Just to be sure, I'm looking for 5VDC max, right? Or is it 12?

:edit: Should I run the test on the IAT also? I don't know how much it matters, but I ripped the underhood insulation off a looong time ago, and since I cut the plastic off of the top of the air cleaner, I don't know how much this affects the IAT.

 

On the TPS max 5VDC at WOT .
The temp sensors you are looking at resistance.
High resistance cold, low resistance hot.
Chart in this thread: https://www.thirdgen.org/techbb2/sho...hreadid=256389

 

I have the chart in one of my automotive technology workbooks.

The CTS acts as normal. The TPS maintains .64 VDC @ idle. I have yet to check the IAT. I found another problem... my intake air box is broke. Don't know how that affects everything, but I'm going to fix it tomorrow.

 

The voltage for the TPS is too high. You need to lower it down to about 0.55V +/- 0.02V.

 

Okay, update.

I put the PCV hose in finally. No vacuum leaks, engine maintains about 15" Hg of vacuum.

Glued the airbox together with silicone caulk. I also sealed the air filter can where the end joins with the MAF. I discovered that the frequency film in the MAF just happens to have a nice wrinkle in it. That's not good, right? Anyone have one from a Camaro I could have? I'm looking to install a PVC duct setup with a K&N filter on the end so I can get rid of the broken crap.

Now, after having installed the PCV hose, the engine runs like a raped ape. However, the engine seems to have a heck of a hesitation in dropping down to idle speed, which I have set at about 800 RPM. There are NO vacuum leaks, like I said before.

:edit: I also adjusted the TPS. I'm still looking at replacement of the TPS, IAT, CTS, and MAF sensors, but the MAF problem is coming first.

 

TTT

Still looking for a Camaro MAF. I do NOT want to have to buy one from GM.

Will go ahead and purchase a GM replacement CTS next week. I am through with buying those el-cheapo rebuilt POS sensors that the major autoparts stores sell.

Reset timing to stock 10* BTDC.

Found another dead plug wire. Replaced with an older wire that's not much better, but has less than 10K ohms resistance per foot, which is recommended.

Reinstalled stock ignition coil, but am leaving the Accel in place for now.

Readjusted TPS to .55 VDC @ idle. I think this sensor is bad also... MAX reading (WOT) is only about 3 VDC, and each time you snap the throttle open and closed you get a different reading, about .1 VDC off of where it's set.

Now, would someone care to explain something? Why is it that the better the engine runs, the worse my mileage is, even if I keep my foot off the gas? I used damn close to a quarter tank paying my insurance today, and that round trip is about 45 miles!